Plasma Nitriding is the most advance technique of surface hardening an engineering component by impregnating the surface with atomic nitrogen.
Also known industrially as ion nitriding, the process establishes an electrostatic field between the furnace wall and the engineering component. Under the vacuum condition, this ionizes the nitrogenous gases and accelerates the ions to bombard, occlude and diffuse into the workpiece matrices.
The microstructure is generally characterized by a thin white layer (3 to 5 Microns thick), with a diffusion zone of alloy nitrides which can measure down to 0.2mm deep. The white layers are hard yet relatively ductile, idea for corrosion and wear resistances.
The diffusion zone, with its induced compressive residual stress, enhances the fatigue performances. Depending on the material chemical composition, processing parameters and service requirements, microstructure with or without the white layer can be produced.
Outstanding characteristics and features of Plasma Nitriding include:
• Good controllability of microstructure
• Uniform and consistent case dept
• Excellent dimensional stability
• Retention of core hardness
The process is applicable to all ferrous materials, such as carbon steels, alloyed steels, tools steels and stainless steels. Titanium-based and nickel-based alloys can be also surface hardened by plasma heat treatment.